Regulation of electric motors.



PATENTED JAN. 30, 1906.

J. G. V. LANG.

REGULATION OI ELECTRIC MOTORS.

APPLICATION FILED JUNE 28, 1904.

2 SHEETS-$113151 1.

PATENTED JAN. 30, 1906.

No.8l1 115.

I J. G. V.-LANG. REGULATION OF ELECTRIC MOTORS.

APPLICATION FILED JUNE 28, 1904.

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JOHAN eiIs'rAF-viKToR LANG; or no'itnon, ENGL ND, assieNoa or 01m HALF TOQEDWARD ncense Jojn soN, OF LONDON, ENGLAND.

nseu 'A rlou- OF sLEoTaio Morons;

' i am and 1m 28', i904. sag-1m. ziesia" 1' To whom) concern/.

TOB LANG,electrician,- a sub'ec't of the King of Sweden and Norway, resi in at 16* .S oho.

Square, London; Eng] and ,have invented certain new and.usefu1 Improvements Relating to the Regulation of Electric Motors, of-whic the following is a specification.

'. 'This invention relates to'the regulation of 'electric motors, particularly those of the kind that are em loyed for propelling vehicles and that wox lt on what is known as the regenerative system, in which the motors act as'such while propelling and accelerating the vehicle and act as dynamos for generat ing and returning electric energy to the source of sup 1 while braking'or retarding the vehicle. l liectric motors Working on the above-stated system were disclosed in a prior United States Patent, No. 767,154, granted to me on the 9th day of August, 1904, and were characterized by the use of a series ex- A citation when propelling and accelerating and of a compound excitation when .braking the vehicle and regenerating current, the change from the one to theother of these two conditions of the motors being effected by the angular movement of acylinder termed a field-change cylinder, which was actuated from the controller-handle in moving in one or other direction with reference! to an particular speed-notch to whichsaid han e might for the time being be set.

, '.The effect of this angular movement of the said field-change" cylinder .was to bring one or other of two series or groups of contacts" tion of the motors. Now it w' l beobvious that with such an arrangement when the anotorma-n shifts the controller-handle from any particular speed-notch to which it has-been.

, Specificatio l'oi Iietters fatentQ-i. I g

' of the "missed J se, eqe."

4 itiol'ler if the motorman Be it known that L-JOHAN GUSTAF VIE-- from ignorance of the fact of such exhaustion or-from" anyother causesliould not continue the backward movement of the controllerhandle to bring it to alo'wer speed-notch the motors (while still -their compound con ;dition) will resume; their propelling functien e mam supp y 69 by receiving-"current (Ii-rpm t instead of s'upplyingc entfitheretmwith the result that themotors will then b manifestly performing a very light duty, and therefore pfperating at a very low. efiiciency,- whereas, at the'moinent-the regenerative exhaustion ,65

took

for converting the motors into their series 5 condition'z. e. in a forward direction-they would be operating at a fairly high efficiency "70 instead of at the very low efficiency mentioned above. l

It isthe chief object of the present inven-.- tion to rovide for the automatic movement change the motors from their compound condition to their series condition whenever the said'motors -(while in their compound condi-. tion) are reaching the de cc of regenerative exhaustion above state so that at such times the change is effected independently of the motorman and by an automatic a ency whose action is absolute and free from a 1 uncertainty.

.''According to this invention and for the purpose ofaccomplishing the aforesaidobg .ject the field-change cylinder is subject'to the I action. of two forces tending to angularly displace it to a limited extent in opposite directions, the predominance of one or other of 0 these forces deciding the direction in which the cylinder will move, and accordingly the condition to which the motors will he changedthat is tosay, whether they will be in their.

said two forces are preferably obtained by a device or contrivance which is partly mechanical. and partly electrical, the lIKClNIH- ical part com rising a spring or asuspended weight and t 10 electrical part comprising al solenoid, an armature movable in a magneticfield, or an electric motor. "lhe mechanical force is constant in its ,action, but the elec trical force only operates at such times when lace the motorman had moved the. 'contro er-handle in the direction necessary" eld-change cylinder to cause it .to '75 The 5 the mechanical force is to be overcome. .Theretore normally the mechanical force predominates and keeps the cylinder in the-{1 OISitlO in which its contacts bring about-it e gserie gt condition of the motors. It, howeli'er, the electrical part of the eontrivanee 's ener y'gi'zed, asis the case when the controllei -handle 1:1s turned m'a backward direct on; s'id electrical part of the contrivancei williiexert a force that will overcome the i iezchanieal force, and thus turn the cylinder iIItQi the position in which its contacts br ng about the compound or regenerative condition of'th'e motors. The circuits of the electrical part or the eontrivanee are )referably such that the initial energization thereof is etfected'lby cur rent from the main electric supply; which if not at once followed by a current from the! anotors. "doesatonce follow the initial current, such re enerative current-will operate to main- .s tam the electrical part of-the eontrivanee enregenerative source, due to the con ipountl condition to which the motors have beeg'i changed by the movement of the fieldehange the eontrivanee to reassert itself and-turn the cylinder back to its normal position, thereby bringing about the series condition of the If, however, a regenerative current ergized, and consequently keep the motors in their compound or regenerative condition. .As soon as the regenerative current ceases,

In order that the said invention may be clearly understood and readily carried into.

effect, the same will be described more fully with reference to the accompanying drawiin s, in which igure 1 illustrates diagrannnatieallv the application of the-aforesahl eontrivanee to the field-change cylinder of a controller which for sake of simplicity is shown for use with a single double-wound motor working on the aforesaid regenerative system, the said motor having four field-coils, which are adapted to be connected in parallel relationship when the motor is propelling and accelerating the vehicle and in series relationship to serve as a slnmt-winding when the motor is regenerating current and braking the vehicle, as set forth in my prior patent mentioned above,

one of the said windings being used as a series winding in whichever condition the motor may be working. Fig. 2- is a plan, and Fig. 3 an elevation, of the aforesaidcontrivancesapplicd to the hold -changc cylinder. Fig. 4 is a plan. and Fig. 5 an elm'ation, of a contact device forming part of the controllercylinder. Figs. 6 and 7 represent diagrammatieally.modified forms of this afore siad con-'1- triva'nee. I

A. represents the main controller-cylinder contacts, and A" the stationary 'rowof contaets withrwhich said main cylinder-contacts cooperate.

A represents a contact with which the boss A and the handle of the main cylinder is provided, (see Figs. 4 and 5,) and A A are stationarycontacts, with which it cooperates.

The aforesaid boss A has radial pins or" projections A lying between stop-pins A on the cylinder A so that the controller-handle is capable of a certain amount of free move ment in either direction in order to bring about the engagement and disengagement of.

the aforesaid contacts without affecting the movement of the main controller-cylinder,

said handle being held'in an intermediate position of its amplitude of free movement by means of spring-pressure.

B represents the field-change cylinder, and B is the row of stationaq cont-acts with which the field-ehtinge-cylinder contacts coo)erate. The vertical line b b represents t 1e series position of the field-change cylinder, and the vertical line b I) re resents the compounding position of said cy inder.

d (1 re resent the armature of the double-woun motor, and e e e e represent the field-coils, the part, c of which is connected with the main circuit at all times.

f f represent the field-regulating resistances, the former for the shunt or compound field and the latter for the series field.

g represents the starting resistance.

' It is a shunt-coil for the circuit-breaker i.

B is the device or contrivance'for actuating the field-chan e cylinder B", said device or eontrivanee in the example illustrated comprising for its electrical part a solenoid pro-' vided with two coils b and b the former of which is a shunt-coil and the latter a series coil. The mechanical part of the contrivance, comprises in the example illustrated a crank-lever b connected with the field- .change cylinder, and a spring I), fixed at one end to a stationary point and at the other end to the extremity of said crank-lever.

In the position in which the parts are represented in Fig. 1 let it be assumed that the mechanical partof thecontrivance is predominating and holding the field-change cylinder in the position in which the motor is in its series condition'i. a, with the contacts in the position b relatively to the row of stationary contacts B-and also let it he assumed that thecontroller-handle is at the first speed-notch of the controller. Then the current flows from the trolle through the coil i to the contact 5 of row B, thence to ICC 8, thence to contact 13 of row B, where the current divides, one part going to earth through field-coil c and contacts 10 and 11 of row A and the other part going to contacts 8, 9, 14, and 15 of row B B, whence it flows through field-coils e, e a, and e, respectively, to contacts 10, 11, 16, and 17, rejoining at contact 12 the first part of the current through c and following the same path therewith to earth. If now the motorrnan desires to convert the motors into their compound or regenerative condition for braking the vehicle, he turns the controller-handle backward andin so doing he first brings the contact A against the stationary contacts A without moving the main controller-cylinder, owing to the aforesaid free movement of the handle,

thereby closing a circuit for the main current through the shunt-coil b of the electrical part of the contrivance before any movement of the main cylinder occurs. The said electrical part of the contrivance thus becomes energized and overcomes the resistance of the spring I) and turns the field-change cylinder B angularly into a position in which the contact-rowli engages with the stationary row B, with the result that the motors are converted into their shunt or compound conditionthat is to say, their braking condition. At the instant the contacts of the said row 6 of the field-change cylinder reach the stationary contacts B a short circuit consisting of the two movable contacts corresponding to 5 and 6 of row B of the main current-path is broken, thereby compelling the generated current obtained from the motors in their shunt or compound condition to pass throu h the coil 5 of the solenoid, and thereafter the current through the coil 6 is broken as the final position b ofthe field-change cylinder is reached, and the solenoid then depends for a continuance of its energy upon the said generated. current. The current then fiows as follows: from the regenerating-motors d (1 over contacts 4 and 30f row A, through coil b of the solenoid B (the short circuit at contact'5 and 6 of row B being broken) to the circuit-breaker, where the current divides, part goin through the coil i and. part going through the shunt-coil h to the trolley and returning through the earth connection over contacts 10 and 11 of row A to contact'12 of row B, through'the compound coil eto the contact 18 of row A and the negative terminal of theregenerating-motor. The field-current is shunted at contact 1, of row A and passes to contact 7 of row B, contact 8, coil e, contactlO, contact 9, coil 0 and contact 11. The current then flows to contact 14,

through coil e ,.to contacts 16 and 15, coil 6, contact 17, and thence to contact 12, where it joins the main current. Obviously when the generated current diminishes to such an extent as to no longer supply the necessary power for keeping the electrical part of the cont-rivance energized the mechanical part becomes again predominant, and its spring 5 automatically returns the field-change cyl inder to the position in which .he motor is in the series condition.

it is necessary to provide for the contingency of requiring the propelling and accelerating function of the motor i. 6., its conversion into the series condition-while the re generative current is still being supplied by the motor, and therefore still keeping the electrical part of the contrivance'active and the field-change cylinder in its compounding position. This contingency would arise if the motorman, having performed a rearward movement of the controller-handle, as stated above, should turn the handle in a forward direction. For meeting this contingency the electrical part of the cont-rivance may be arranged in a circuit which enables it to be deenergized by the main current being sent around the solenoid in an opposite direction to that which it previously flowed or by shortcircuiting the said solenoid. In the drawings the latter provision is made, so that on the forward movement of the controller-handle the contacts A become engaged, and the thenactive coil 1) of the solenoid is short-circuited, thereby rendering said solenoid dormant and permitting the mechanical part of the contrivance to become redominant, thus turning the field-change cy inder into the position for converting the motor into the series condition, as explained above.

It will of course be understood from the foregoing description that after the controllerhandle has been moved in either direction to bring about the engagement of the contacts A or the contacts A the further continued -movement of said handle will operate the main controller-cylinderin the ordinary manner and bring about the necessary change of contacts for effecting the changes in speed of the motor. It has not been thought necessary to describe the various steps in the movement of the main controller-cylinder and the alteration in circuits resulting therefrom in order to bring about the speed changes, as these operations are well understood.

A further advantage arising from the fact that onthe failure of the motor to supply current during its regenerative working it automatically assumes its series condition is as follows: It is well known that if the connection between a regenerative motor equi merit and the source of electric supply shou d be broken while. the motors are in theirregencrating or compound condition and that if the potential energy of a gradient or the continued backward movement of the controllerhandle should cause an increase of the gener- IIO ating efiic'icncy of the motor equipment to take place the generate voltage due to the motors working as dynamos may rise to such an extent as to jeopardize the safety of the the limit predetermined for it closes a circuit IO.

through the coil of the shunt-field switch and causes it to brake the shunt-field circuit. By the hereinabove-described contrivance this protection of the motors isafforded without the need of other or special devices, because in the event of connection with the source of supply being lost no regenerative current can pass to the line, and therefore none can pass through the winding 7) of the solenoid with the result that the latter will no longer keep the fieldchan e cylinder in its motor-compounding condition .and the mechanical part of the contrivanoe will turn said cylinder into the position for converting. the motor. into the series condition. Another advantage afforded by the present invention is the reduction of the size and complication of .the ordinary platfornt1-controllers used on tramway c'ars, in that only one of the aforesaid automatically-operative field-change cylinders is required for each car, which cylinder may be placed underneath the car in a suitable casing and be mechanically independent of the plat form controllers. The number of electric leads to the controllers are also greatly reduced, because the field-coils terminals need only be .led to the single automatic fieldchange cylinder instead of, as heretofore, to two field change cylinders, each of which constituted part of the platform-controllers. A still further advantage arises in the nature of an added factor of safety which results from the arrangement of the shunt it around the usual circuit-breaking coil 1'. and the provision of the field-change cylinder with means" for bringing it into use only when the equipment is performing its regenerating function, the contact 1 of the row B completing the circuit through the shunt h. The motor can thus be called upon to perform a much higher duty with respect to retarding factors than is generally considered to be the proper limit of accelerating duty,

can. be adjusted to increase the carrying capacity'of the load-limiting switch to any desired extent. The function of the ordinary overload -switch is to protect the motor from damage by'too great a current, the limit of the current being chosen accordingly. During the period that'the motor is acting in its compound or regeneratingcondition for braking the vehicle another and more important consideration arises-viz., the avoidance of collision and danger to life of the passengers, and this is met by this invention by b may because the shunt-path are the employment of for the O'VfiilGittl-SV Although the cons ivance for oscillating the field-change cylinder has been hereir scribed as being partly electrical and pa mechanical, which is preferable, it is pos.

Wholly elec rical in its action on. the field cha'nge cylinder by the employment of a relay, as represented in .2 of the drawings. In this case the crank if of the field-change cylinder is subject to the action of two solenoids b l), arranged on op iosite sides thereof, with contactsb 5 in the circuit of their windings. The tongue I) of the relay is normally keptpressed against the contact I) by a light'spring'b oi a weightfwhereby the main circuit will flow around the solenoid b in the direction necessary for causing it to actuate the crank b and turn the fieldchange cylinder into the position required for the series condition of the motor. When, however, the controller-handleis turned in 'the backward direction, as aforesaid, to bring about the com ound condition of the motor, the contact ,'Fig. l, engages the contacts A and ClOSGS tlIG circuit throughthe shunt-coil b ofthe electromagnet B, Fig. 2;

The tongue I) of the relay is thus attracted.

and caused to engage the contact b thereby reversing and the solenoid b inoperative, thus reversing the position of the field-change cylinder, as in the previous case when the shimt-coil Fig. 1, was excited. Subsequently the shunt-coil 5 Fig 2,'is thrown out of circuit, as before, and if the motor in its compound condition generates current of sufficient vol tag'e the series coil 6 of the electromagnet is energized and maintains the tongue b 'in its shifted position in engagement with the conv tact 1) until such time as the regenerated. current falls too'low or the motor is changed back-to the series condition, as already explained.

If desired, one of the aforesaid solenoids b be substituted by a s ring 6, as shown in Fig. 3, in which case 0 )viously only one of the contacts l)" l) would be required.

Vhat I claim, and desire to secure by Lctters Patent of the United States, ls- I 1. In regenerative motor controlling means,'the combination with the main controller-cylinder and the fieli'l-changc cylimler,

of means whereby the said field-change cylindenwill automatically change the motor from its compound or shunt condition to its series condition, whenever the regenerated current of said motor, while in its compound or regenerative condition, falls below a predetermined value for the purpose specified.

2. In regenerative I means, the combination with the main conthe direction of the current and causing the solenoid b to become energized motor controlling to so arrange the said contrivance t it is troller-cylinder and the field-change cylinder, of means that tend to keep the field-change cylinder in the posit-ionifor bringing about t e series condition of the motor, means whereby the field-change cylinder is moved against the resistance of the first-mentioned means into the position for bringing about the compound or shunt condition of the motor, and means whereby the reduction in the re enerative current below a predetermined 'va ue permits the firstment1oned means to become dominant and to automatically return the field-change cylinder to its original position forthe purpose specified.

' 3. In regenerative motor controlling 7 means, the combination with the main con- 1 troller-cylinder and the field-change cylinder,

of a maglrliletoelectrical device, shunt and series win 'gs thereon, means whereby the initial movement of the handle of the main 0011- troller-cylinder causes the shunt-winding to be momentarily energized and the fieldchange cylinder moved into the compound organizing position with relation to the motor, and means whereby the regenerative current energizes the series winding and -maintains said cylinder in its shifted position so long as'saidcurrent does not fall below a predetermined value, substantially as and for the purposes described.

4. In regenerative motor 1 controlling means, the combination with the main'cont-roller-cylinder and the field-change cylinder, of a solenoid having shunt and series wind-- ings, circuits connecting said windings to fixed contacts at the main controller-cylin-.'

der, contacts on the handle of the maincontroller-cylinder cooperating with the fixed contacts for enabling the shunt-winding of the solenoid to become energized, contacts 

